Review helpfulness

1. datasets

1.1. Google play

1.2. steam

1.3. Amazon

1.4. Trip Advisor

1.5. Digital library databases

1.6. Yelp

2. Techniques

2.1. Regression

2.2. Fisher's Z and combine effect sizes

2.3. Rolling window

2.4. Classification

2.5. Descriptive statistics

2.6. Prediction

3. Evaluation method

3.1. Performance metrics

3.1.1. Accuracy

3.1.2. Sensitivity

3.1.3. Precision

3.1.4. Recall

3.1.5. F-measure

3.2. Error-based measures

3.2.1. Root relative squared error

3.2.2. Relative absolute error

3.2.3. Root mean squared error

3.2.4. Mean absolute error

3.3. Comparing and benchmark

4. Attributes

4.1. Review attributes

4.1.1. Depth

4.1.2. readability

4.1.3. Sentiment (valence)

4.1.4. Length

4.1.5. Life

4.1.6. Rating

4.1.7. Number of votes

4.2. Reviewer attributes

4.2.1. Expertise

4.2.2. History

4.2.3. Recency

4.2.4. Credibility

4.2.5. Information disclosure

4.2.6. Ranking

4.2.7. Expert label

4.2.8. Monetary

4.2.9. Reputation

4.2.10. Image

4.3. Platform attributes